code: def test_initialize_lengthscale_batch(self):
      kernel = CategoricalKernel(batch_shape=torch.Size([2]))
      ls_init = torch.tensor([1.0, 2.0])
      kernel.initialize(lengthscale=ls_init)
      actual_value = ls_init.view_as(kernel.lengthscale)
      self.assertLess(
          torch.linalg.norm(kernel.lengthscale - actual_value), 1e-5
      )
  
file_path: botorch/test/models/kernels/test_categorical.py
imports: import torch
  from botorch.models.kernels.categorical import CategoricalKernel
  from botorch.utils.testing import BotorchTestCase
  from gpytorch.test.base_kernel_test_case import BaseKernelTestCase
label_desc: Use image node_id 6 for calling the TestCategoricalKernel obj's underlying member method code with example usage: obj.test_initialize_lengthscale_batch() without return types